Bonus skill decays every second day.
I unlocked the bonus skill level "Christmas" for the Spanish for English speakers module. After I completed the skill, it decays every other day. The past few week, I refresh it every time to get it back to full strength but then it decays again in 2 days like clockwork. This does not happen for regular skill levels.
Unfortunately this is because the vocabulary words don't cycle through your lessons practices (except under rare occasions), and if you use a vocab word for the Christmas section in another lessons you don't get credit; unlike other skills where if you practice él in one lesson, you get 'credit' for it, even if you weren't reviewing that particular skill.
The good news is, the decay rate does slow down. I haven't studied Christmas in 2 weeks, and I am still golden (I bought it when it first came out, and always immediately made it gold again). But, for this to work, you have to be very careful to get your answers correct and not peek (both these things will make the Skill decay faster).
Based on my other vocabulary decay rate, I think it bottoms out at 2 months. So, if you stay consistent, eventually you only have to practice every 2 months.
This is the way it should work. If its not working this way for you, move this thread over to troubleshooting and see if someone from the staff can help you out. You can also email support.
Yes- I've noticed something similar for the German Bonus skill "Idioms." I think the Bonus skills still need a bit of refactoring.
1) The bonus skills definitely seem to decay faster than others. 2) Practicing those skills does not refresh them back to gold as fast as other skills do. 3) Looking at the vocabulary "Show all words in this Lesson" does not include any of the words that are specific to that skill (e.g. Holzweg, Daumen, Eimern).
Is this an issue that should be submitted to "Support," or is it sufficient to post it here?